Baby Blue?
by CJS51703
Summary: It was supposed to just be a visit to the lab for Swap and Blue. But, whenever Blue gets curious with what he finds, they get a little bit more than they bargained for... (Underswap)
1. Chapter 1

*****Hey, guys. This is something I actually thought of a while ago, but this is the first time I've ever written it. A quick guide of who's who: Swap is Papyrus, Blue is Sans, Dr. Undyne is Undyne, and Alpha is Alphys. Now that that's cleared up, I own absolutely nothing and let's begin!**

Swap knocked on the door to the lab with Blue standing by his side. After a few moments, Dr. Undyne appeared at the door. "B-boys! C-come on in," she said

So the brothers came inside. "Where's Alpha?" Blue asked, looking around for his best friend. "Oh...sh-she's sick. It took a-all I h-had to convince her that she n-needed to stay in b-bed and r-rest for the d-day," Dr. Undyne said.

Blue's shoulders sunk in sadness. "Darn it," he said. "Don't take it so hard, bro. Just come along to the lab with us. I'm sure you can find something that's safe for you to do. You _do_ promise you won't mess with anything and be careful...right?" Swap asked.

Blue nodded. He had never been allowed inside the lab. Besides, his training with Alpha was usually outside. That, or they took over the kitchen for a cooking lesson.

So with that, the three went to the lab.

XxX

An hour passed. Swap and Dr. Undyne had been very interested in the things they were doing.

Blue, on the other hand, was and had been bored out of his mind. Until he came across something that peaked his curiosity.

It was a machine pressed into the back corner. It looked an awful lot like a photo booth, save for the opened automatic door where a curtain would have been.

Curious, Blue went in. He saw several colored buttons in front of him after he sat down. So, he pressed each and every one of them.

That was his fatal mistake.

The automatic door slammed shut, sealing him inside. He started banging on the machine, yelling and pleading for help.

Alarmed, Swap and Dr. Undyne rushed over to the machine. "One m-moment," Dr. Undyne said. She typed madly at her laptop, trying to shut down the sparking and vibrating machine before her. "I c-can't shut it d-down!" she cried at last.

Swap used a different tactic. He simply summoned a Blaster and blasted the machine to bits.

Dr. Undyne was a bit mad about her machine being destroyed. But she knew it was for a good reason. So she and Swap went into the remains of the machine and started digging through the rubble. Luckily, they found Blue still alive and unharmed.

But they also saw that he had become a baby.

 *****How coincidental...Alpha is sick and so am I. Anyways, be sure to drop a review on the way out. I'll see everyone in chapter two. Bye!**


	2. Chapter 2

*****Hey, guys. With exams as well as my birthday coming up, I figured you all deserved one more chapter before I went. So, I own nothing but the story, and here we go!**

Dr. Undyne nearly had a stroke. "H-holy Christ, I am s-so sorry. I'll f-fix the machine as s-soon as p-possible. C-cross my SOUL," she rambled.

Swap put his finger to her lips to shut her up. "Calm down. Just fix the thing soon. Don't have a panic attack on me," he said.

With that, he picked up Blue and carried him out of the lab.

XxX

Opposite to his usual nature, Swap was freaking out. He didn't know the first thing about taking care of a baby. After about an hour of being on the verge of a panic attack, he gave into his desire. He took a cigarette from his pocket, lit it, and started smoking it. Sure enough, his nerves had been settled after a few moments.

But the peace didn't last. Blue burst into tears. So Swap picked him up. "Please tell me you don't need a diaper change," he pleaded, not counting on getting any answer.

A solid twenty minutes passed without any sort of changes.

Swap finally held Blue at arm's length by his underarms and cried out, "What do you need?! I'm about to have a nervous breakdown over here!"

Blue pointed towards the cigarette, still crying. Swap took out the cigarette and tossed it into the trash. "Happy now?" he asked. Blue quieted down immediately and went back to his usual happy smile.

"Note to self: don't smoke with him around."

XxX

About an hour passed. Things had been pretty quiet, to be honest. The skelebros were just chilling in the living room. Until Blue's stomach started rumbling. He burst into tears and began having yet another fit.

This one was a lot easier for Swap to figure out. "Alright. Hang on one sec. I'll be right back with some food," he promised. He then took a shortcut to Muffet's and went right up to the bar.

"Ah. How are you doing today?" Muffet asked, as she usually did. "I don't have time for small talk right now. Can ya hit me up real quick with an order of fries to go?" Swap asked.

Muffet nodded. She skated back into the kitchen and came out a few moments later. "Here you go," she said.

Swap took the bag. "Thanks. Just put it on the tab," he said. And with that, he took a shortcut back to his house.

Muffet sighed. She went towards her office, which was near the back of the establishment. After going in, she took out a stack of papers that was held together by staples and added yet another item on the list that was on it.

"If he doesn't pay his God-darn tab soon..."

XxX

Blue was still throwing his fit. Swap carried him to the kitchen and put him on the table. He picked up a fry, broke it in half, and offered it. Denied. "Come on, it's good," he said.

But Blue still pushed it away. He pointed to a recently-bought taco-making kit that was out on the counter still.

Swap picked up the box as he examined it. "But I can't cook for the life of me," he said. But Blue kept pointing to it. So Swap opened up the box and began spreading its contents across the counter.

"Now, let's see here..."

XxX

One kitchen fire and gigantic mess later, the tacos were done.

Swap took off his stained hoodie and threw it towards the living room. He'd have to wash it later. Making a mental note of doing that, he put a taco on a paper plate and crossed the kitchen with it. He tore off a small bit of it and offered it. "Eat up, little guy," he said.

Blue took the bit and shoved it into his mouth with no hesitation at all. This process repeated itself until the plate was empty. When he was finished, Blue looked awfully sleepy. "Me too," Swap agreed.

He picked up his brother and carried him to his room, putting him in his bed and watching him fall asleep in no time at all.

After Blue was asleep, Swap went down to the living room couch, collapsed on it, and did the same.

 *****So, a review would make an awfully nice birthday present for me...be sure to drop one as you go. In the meantime, I will see everyone later! Bye!**


	3. Chapter 3

*****SURPRISE! Yeah, I know I said that I would be gone for exams. But I found out that they don't start until Friday. So here is this new chapter of this. I own nothing. So, let's do it to it! (Those who get the reference earn imaginary cookies.)**

A week had passed. Swap had slowly gotten adjusted to having to look after a baby. The only thing he hadn't quite mastered yet was the diaper changing. But Blue wasn't too difficult to deal with. To put it simply, things were going rather well. Currently, Swap was lounging on the couch with Blue laying on his rib cage.

"I tell ya, bud. It hasn't been easy taking care of this baby version of you. But, quite honestly, you are pretty adorable. Although I do want the Doc to fix her machine, I believe I'd be okay with you staying a baby for a while," he monologued profoundly.

"Suh...suh...swuh...swah..." Blue began. He looked like he was frustrated. Swap's eye sockets widened in his shock. "Holy Christ," he said simply.

"Swuh...swah...Swap!" Blue said. He began saying his big brother's name over and over happily.

Swap found himself wiping tears from his eye sockets and off of his face. He hugged Blue into his rib cage, trying to not crush him entirely.

"Atta boy."

XxX

A short time went by. The house phone rang from the kitchen. So, Swap picked it up to answer.

"What's up?"

"Th-this is D-Dr. Undyne."

"Oh. Hey, Doc. How're things coming with the machine?"

"Th-that's actually what I w-wanted to t-talk to you about."

"Okay."

"The m-machine's finished. Come b-by whenever you p-please."

"Can I come by right now?"

"Y-yes."

"See ya in a sec."

With that, Swap hung up. He went back to the living room and picked up Blue. "Come on, bro," he said. "Let's go bring you back to normal."

Then, they took a shortcut to the lab.

 *****Yeah, yeah, I know it was short. But hey, it's better than nothing. Welp, be sure to leave a review and I'll see you all in chapter four. Bye!**


	4. Chapter 4

*****Hey, guys. Just thought I'd finish up this story before I have to be offline for a while. To put it simply: I own nothing but the plot. So, without further ado, let's begin!**

Because they took a shortcut, the skelebros got to the lab in a matter of seconds.

"H-hi, guys. Are you r-ready for the s-switch back?" Dr. Undyne asked. Alpha, who had been most likely told about the switch and who had long since gotten over her sickness, was standing there as well.

"I am. Let's do this," Swap said. "But b-both of you have to b-be in the m-machine. To m-make your age pr-proportions the same again. Put Blue d-down on the s-seat, though. G-go on in," Dr. Undyne explained.

Swap nodded. He went inside, put Blue on the seat, and leaned against the wall while waiting. Just as he'd been told to do. The two brothers were soon sealed inside of the machine.

Dr. Undyne started typing on her laptop, DETERMINATION to fix her mistake written across her face. "You'll hurt yourself if ya get any more intense," Alpha warned teasingly. "Sh-shut it," Dr. Undyne said, her focus still not breaking.

The machine activated at last. It shook and it sparked as it had during its last run for a few moments before it calmed back down. The automatic door slid back open.

And out came the skelebros...only this time, they came out as little kids.

Neither of them could have been more than eight or nine years old. Dr. Undyne and Alpha looked at each other before looking back at the two brothers.

"That's good enough for me. Come on, Blue!" Alpha said. She grabbed Blue's hand and pulled him along, most likely for a training session.

"G-God! Freaking! D-dangit!" Dr. Undyne cried out in exasperation, banging her head on the counter with each word. She put her head down until she could see straight, then she stood up and readjusted her glasses. "I'm t-terribly sorry about a-all this. I'll keep t-trying to t-turn you two b-back to n-normal," she promised.

"It's fine, Doc," Swap said. He took a candy cigarette from his pocket and treated it just as he would have if it was one of his normal ones. If there was anything that Dr. Undyne was certain of, then it was this:

That no matter what age Swap and Blue were, they would never truly change.

 **The End**

 *****Bet you didn't see that coming, huh? Well, I gotta go to school now. So be sure to drop a review as you go and I'll see you all next time. Bye!**


End file.
